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Appendix B About Wireless LANs
Linksys
38
Appendix B About Wireless LANs
Overview
Wireless networks have their own terms and jargon You must understand many
of these terms in order to configure and operate a wireless LAN
Wireless LAN Terminology
Modes
Wireless LANs can work in either of two (2) modes:
•
Ad-hoc
•
Infrastructure
Ad-hoc Mode
Ad-hoc Mode does not require an access point or a wired (Ethernet) LAN
Wireless stations, e g , notebook PCs with wireless cards communicate directly
with each other
Infrastructure Mode
In Infrastructure Mode, one or more access points are used to connect wireless
stations, e g , notebook PCs with wireless cards to a wired (Ethernet) LAN The
wireless stations can then access all LAN resources
NOTE
Access points can only function in Infrastructure Mode, and
can communicate only with wireless stations that are set to
Infrastructure Mode
SSID/ESSID
BSS/SSID
A group of wireless stations and a single access point, all using the same ID (SSID),
form a Basic Service Set (BSS)
Using the same SSID is essential Devices with different SSIDs are unable to
communicate with each other
ESS/ESSID
A group of wireless stations, and multiple access points all using the same ID
(ESSID), form an Extended Service Set (ESS)
Different access points within an ESS can use different channels To reduce
interference, it is recommended that adjacent access points SHOULD use
different channels
As wireless stations are physically moved through the area covered by an ESS,
they will automatically change to the access point that has the least interference
or best performance This capability is called roaming (Access points do not
have or require roaming capabilities )
Channels
The wireless channel sets the radio frequency used for communication
•
Access points use a fixed channel. You can select the channel used. This
allows you to choose a channel that provides the least interference and best
performance For USA and Canada, the following channels are available
2 .4GHz :
2 412 to 2 462 GHz; 11 channels
5GHz:
•
5.180 to 5.240 GHz; 4 channels
•
5.745 to 5.825 GHz; 5 channels